1. Field of the Invention
This invention relates generally to an electrical discharge machine, particularly to a power supply module of an electrical discharge machine.
2. Description of the Prior Art
An electrical discharge machine (EDM) is considered an indispensable tool for processing molds nowadays, and the working conditions of a discharge power supply concerns with the surface coarseness of worked pieces, processing efficiency, electrode and energy consumption, etc.
As illustrated in FIGS. 2A and 2B, during discharge processing, the surface characteristics of a worked piece depends on the peak value (Ip) and pulse width (xcfx84p) of the discharge current while the processing efficiency on the break time (xcfx84r), and a discharge circuit is provided for control of the waveform of the discharge current to meet various requirements.
Referring to FIGS. 1, 2A, and 2B, the discharge circuit is mainly composed of a direct current (DC) discharge power supply, a limit resistor (R), a transistor (T1), and diodes (D1, D2) in connection with a working electrode P for preventing any reverse current. If the transistor (T1) is turned on, a DC voltage will be generated between two electrodes (P) to create discharge phenomenon, usually expressed in sparks, in case the gap between those electrodes is narrow enough, then, after time xcfx84p+xcfx84n has elapsed, the transistor (T1) is turned off to have the current paused. When the transistor is controlled in such a way repeatedly, a train of waveforms of discharge current as shown in FIGS. 2A and 2B can be obtained.
The discharge power supply of EDM generally comprises a high-voltage and a low-voltage circuit (90), (91) concurrently as shown in FIG. 3, wherein a high-voltage power supply (VH) rated 100Vxcx9c200V serves for an arc introducer to raise the discharge efficiency and stability while a low-voltage power supply (VL) rated 60Vxcx9c100V is used to provide electric energy for discharge processing in different current stages.
Practically, a discharge power supply board or two are made according to predetermined energy stages for disposing the high-voltage and the low-voltage discharge circuit (90), (91) together in one board or separately in two boards and wire-coupled with a control signal (94), a DC power supply, a limit resistor, a discharge electrode (95), and a workbench (96) to form a discharge power supply system, which is somewhat petrified for expansion and installation basing on planned stages of discharge voltage and current with complicated wiring and rather difficult maintenance.
In view of abovesaid defects, after years of constant effort in research, the inventor of this invention has consequently developed and proposed a module mechanism of discharge power supply system.
The primary object of this invention is to provide an electrical discharge power supply modular device for building discharge power supply in a module for easy installation and maintenance.
Another object of this invention is to provide an electrical discharge power supply modular device for building and adjusting a plurality of discharge power supply modules by using a discharge power supply module setting device for flexibly splicing an expandable multistage discharge power supply.
Yet another object of this invention is to provide an electrical discharge power supply modular device for reducing wiring and inductive effect.
A further object of this invention is to provide an electrical discharge power supply modular device fit for mold-engraving discharge, fine-hole discharge, etc.
For realizing abovesaid objects, an electrical discharge power supply modular device for electrical discharge machine comprises at least a discharge power supply motherboard having a discharge power supply control signal bus and a plurality of coupling devices of discharge power supply circuits for flexibly accommodating several discharge power supply modules, finishing circuit modules, and special processing circuit modules to form a multistage discharge power supply controlled by a discharge signal generator for providing discharge clock pulses to all the discharge power supply circuits so as to proceed electrical discharge.
For more detailed information regarding this invention together with further advantages or features thereof, at least an example of preferred embodiment will be elucidated below with reference to the annexed drawings.